Shares of the innovative clinical-stage biotechnology company bluebird bio Inc. (NASDAQ: BLUE) have jumped more than 13% Tuesday, after the company together with their partner Celgene Corporation (NASDAQ: CELG) reported updated results from the ongoing CRB-401 Phase 1 clinical study of bb2121, an investigational anti-BCMA CAR T cell therapy, in 18 patients with relapsed/refractory multiple myeloma. Shares are up more than 67% year to date.

The objective of this Phase 1 dose-escalation study is to evaluate safety and efficacy of bb2121 and determine a recommended Phase 2 dose. bluebird bio and Celgene are jointly developing bb2121.

Highlights:

• 100% of the 15 evaluable patients in active dose cohorts (doses above 50 x 10⁶) achieved an objective response; overall response rate (ORR) across all cohorts (n=18) is 89% 
• 73% of evaluable patients in active dose cohorts achieved a very good partial response (VGPR) or better; 27% complete response (CR) rate across active dose cohorts 
• All patients tested for minimal residual disease (MRD) status (n=4) were found to be MRD-negative 
• No disease progression has been observed in active dose cohorts as of May 4, 2017 data cut-off; range of follow-up was 8 to 54 weeks
• No dose-limiting toxicities have been observed 

“It is impressive to see objective responses in all patients treated at dose levels of 150 x 10⁶ CAR+ T cells or higher in such a heavily pretreated population, including those with high tumor burden. We are encouraged by the duration and depth of responses, and pleased that the safety profile remains readily manageable,” said David Davidson, M.D., chief medical officer, bluebird bio. “Although these data are still early, it is encouraging that no patient in the active dose cohorts has had myeloma progression. In light of these results, we look forward to initiating the expansion phase of the CRB-401 study in the coming months.”

“The heavily pretreated, relapsed/refractory patients in this study have few effective treatment options, highlighting the importance of this interim data. All patients previously underwent autologous HSCT, and received a median of 7 lines of prior therapy,” said Michael Pehl, President, Hematology and Oncology for Celgene. “The consistency, depth and durability of these patients’ responses coupled with a manageable safety profile is very exciting, and we believe will provide hope for patients in this setting. Efforts are underway to advance the development of bb2121 for patients with relapsed/refractory multiple myeloma.”

bluebird bio’s oncology pipeline is built upon the company’s leadership in lentiviral gene delivery and T cell engineering, with a focus on developing novel T cell-based immunotherapies, including chimeric antigen receptor (CAR T) and T cell receptor (TCR) therapies. bluebird bio’s lead oncology program, bb2121, is an anti-BCMA CAR T program partnered with Celgene.